This invention relates to an apparatus for sputter coating glass, and corresponding method.
Sputter coated glass articles are known in the art. For example, see U.S. Pat. Nos. 5,770,321, 5,298,048, and 5,403,458, the disclosures of which are all hereby incorporated herein by reference. Sputter coated layer systems on glass substrates are typically utilized for achieving solar management properties (e.g., low emissivity or low-E) in many types of glass articles, including but not limited to architectural windows, automotive windows, automotive windshields, and the like.
Sputter coating may be an electric discharge process, often conducted in a vacuum chamber in the presence of one or more gases. A sputter coating apparatus typically includes at least one vacuum chamber in which a substrate is located, a power source, an anode, and one or more specially prepared cathode targets of or covered with a material to be used in creating a layer on the substrate. When an electric potential is applied to the cathode target, the gas(es) forms a plasma that bombards the target causing particles of the coating material to be liberated or lifted from the target itself. The liberated coating material from the target falls onto the underlying substrate and adheres thereto. When conducted in the presence of a xe2x80x9creactivexe2x80x9d gas, a reactive product of the coating material from the target and the gas may be deposited on the substrate.
Unfortunately, conventional sputter coating apparatuses suffer from certain inefficiencies, especially when one desires or needs to manufacture different types of sputter coated articles using the same sputter coating apparatus.
Consider, for purposes of examples only, a scenario where one wishes to manufacture the coated articles of FIGS. 1 and 2 utilizing a sputter coating apparatus. The coated article of FIG. 1 includes glass substrate 1 on which are located silicon nitride (Si3N4) layer 2, nichrome or nichrox (NiCr or NiCrOx) layer 3, silver (Ag) layer 4, nichrome or nichrox (NiCr or NiCrOx) layer 5, and silicon nitride (Si3N4) layer 6. Optionally, another layer (e.g., a dielectric layer) may also be provided between substrate 1 and layer 2. Further details regarding the coated article of FIG. 1 may be found in U.S. Pat. No. 5,770,321, incorporated herein by reference. Meanwhile, the coated article of FIG. 2 also includes layers 2-6 provided on glass substrate 1. However, the coated article of FIG. 2 further includes a thicker silicon nitride (Si3N4) layer 6a (instead of layer 6 shown in FIG. 1), nichrome or nichrox (NiCr or NiCrOx) layer 7, second silver (Ag) layer 8, nichrome or nichrox (NiCr or NiCrOx) layer 9, and silicon nitride (Si3N4) layer 10. The coating system of FIG. 2 may be referred to as a dual silver coating system because it includes first and second silver (Ag) layers 4 and 8 provided for infrared (IR) radiation reflection, respectively, as opposed to the single silver layer 4 provided in the coated article of FIG. 1.
To manufacture both the coated article of FIG. 1 and the coated article of FIG. 2 using the same sputter coating apparatus, one would typically obtain a sputter coating apparatus as shown in FIG. 3. The FIG. 3 sputter coating apparatus includes enough targets and zones to enable each of layers 2-10 to be deposited on a substrate 1 (i.e., it is large enough and has enough capacity to enable either the FIG. 1 or the FIG. 2 article to be made therein). In particular, the sputter coating apparatus includes six different zones (i.e., zones 1-6) which are separated from one another by curtains or walls 52. Zone 1 includes targets 21-26. Zone 2 includes targets 27-29. Zone 3 includes targets 30-35. Zone 4 includes targets 36-41. Zone 5 includes targets 42-44. Zone 6 includes targets 46-50. A different gas (e.g., argon, nitrogen, oxygen, etc.) may be utilized in each zone at low pressure, while vacuum pumps 51 are provided between zones in order to keep gaseous atmospheres from one zone from significantly leaking into an contaminating adjacent zone(s).
In order to manufacture the coated article of FIG. 1 using the sputter coating apparatus of FIG. 3, a typical line speed of the sputter coater is 205 inches per minute for this five layer system. For the FIG. 1 coating system to be deposited, targets 21-26 in zone 1 are silicon (Si) targets, while nitrogen gas at low pressure is provided in that zone. Following deposition of silicon nitride layer 2 in zone 1 using targets 21-26, the substrate 1 passes into zone 2 via a conveyor. In zone 2, targets 27 and 29 are of nickel and/or chrome, while target 28 is of silver. An argon (Ar) atmosphere may be utilized in zone 2. After the nichrome layers 3 and 5 and silver layer 4 are deposited in zone 2, a conveyor moves the substrate into zone 3 beneath targets 30-35. In zone 3, targets 30-35 are of silicon (Si) while a nitrogen (N2) gas at low pressure is utilized in that zone. Each of zones 1-3 may be maintained at a pressure of from about 1.0 to 3.0xc3x9710xe2x88x923 Torr, or any other pressure disclosed in any of the aforesaid ""321, ""048 and ""458 patents. Upon leaving zone 3, the coating system of FIG. 1 will have been formed. Thus, zones 4-6 and their respective targets 36-50 are inoperative in the FIG. 3 apparatus when the coated article of FIG. 1 is deposited as discussed above. Unfortunately, the inoperation of these three zones 4-6 is wasteful, and also presents a requirement for passing a coated article through inoperative zones thereby leading to potential contamination and/or undesirable delay.
However, when it is desired to manufacture the coated article of FIG. 2 utilizing the apparatus of FIG. 3, zones 1-3 are set up and utilized as described above regarding the FIG. 1 article. In addition, zones 4-6 are set up just like zones 1-3, respectively. Thus, the upper half of silicon nitride layer 6a and layers 7-10 are deposited in zones 4-6. In other words, targets 36-41 are silicon targets in a nitrogen atmosphere of zone 4, targets 42 and 44 are nickel and/or chrome targets in an argon atmosphere in zone 5, target 43 is a silver target in the same argon atmosphere of zone 5, and targets 45-50 are silicon targets in a nitrogen atmosphere of zone 6. Thus, all six zones (i.e., zones 1-6) are utilized when forming the layer system of the FIG. 2 coated article.
Unfortunately, as can be seen from the above, it is often desired to manufacture coated articles of different types such as those of FIGS. 1 and 2. If this is to be done utilizing the same sputter coating apparatus, such an apparatus must be obtained which has enough zones and targets to enable the coating system having the largest number of layers to be manufactured. Thus, one desiring to manufacture the articles of both FIG. 1 and FIG. 2 would have to purchase a sputter coating apparatus such as that shown in FIG. 3 having sufficient zones and targets to accommodate the FIG. 2 article. Unfortunately, many of these zones and targets are wasted and not utilized when only the article of FIG. 1 is manufactured (i.e., certain zones and/or targets would likely be inoperative during manufacture of the FIG. 1 article). In other words, a significant portion of the coating apparatus may not be used when certain coated articles having a small number of layer(s) are being manufactured. Yet another problem is that when it is desired to upgrade a particular sputter coating apparatus, the line (i.e., all zones 1-6) must be shut down.
In view of the above, it will be appreciated by those skilled in the art that there exist a need for a sputter coating apparatus which can more efficiently manufacture sputter coated articles of different types without wasting significant resources (e.g., zones and/or targets). There also exists a need in the art for a corresponding method.
It is a purpose of different embodiments of this invention to fulfill any and/or all of the above described needs in the art, and/or other needs which will become apparent to the skilled artisan once given the following disclosure.
An object of this invention is to provide a sputter coating apparatus capable of more efficiently depositing different types of sputter coated layer systems.
Another object of this invention is to provide a sputter coating apparatus including first and second sputter coating lines that are selectively coupleable to one another via a transition zone. Each of the first and second sputter coating lines may be independently utilized to deposit particular coating systems on a substrate. However, when it is desired to deposit a coating system having more than a predetermined number of layers (e.g., a layer system having more layers than either of the lines is capable for depositing), the transition zone couples the two lines together thereby enabling an incompleted sputter coated article leaving the first sputter coating line to be routed to the second sputter coating line so that additional layer(s) may be sputter coated thereon. Thus, the two sputter coating lines may be used either independently (e.g., run in parallel to one another), or alternatively may be used in conjunction with one another (e.g., run in series with one another).
Yet another object of this invention is to fulfill any and/or all of the aforesaid objects and/or needs.
Generally speaking, certain embodiments of this invention fulfill one or more of the above-listed needs and/or objects by providing a sputter coating apparatus comprising:
a first sputter coating line including a plurality of zones and a plurality of targets;
a second sputter coating line including a plurality of zones and a plurality of targets; and
a transition zone coupled to the first sputter coating line and the second sputter coating line, said transition zone selectively coupling the first and second sputter coating lines to one another so that when not coupled to one another the first and second lines can run in parallel with one another and when coupled to one another by the transition zone the first and second lines run in series with one another.
Certain other embodiments of this invention fulfill one or more of the above-listed needs and/or objects by providing a method of sputter coating a glass substrate, the method comprising the steps of:
providing the glass substrate;
causing the glass substrate to pass through a first sputter coating line including a plurality of zones and a plurality of targets so that at least first and second layers are sputtered onto the first substrate in the first sputter coating line;
determining whether it is desired to provide additional layers on the glass substrate, and if so then upon the glass substrate exiting the first sputter coating line causing the glass substrate to be forwarded to a second sputter coating line including a plurality of zones and a plurality of targets; and
causing the glass substrate to pass through the second sputter coating line so that at least third and fourth layers are sputtered onto the first substrate over the first and second layers in the second sputter coating line.